1/* Add SORT_BY_ALIGNMENT to linker script (found in busybox_unstripped.out): 2## .rodata : { *(.rodata SORT_BY_ALIGNMENT(.rodata.*) .gnu.linkonce.r.*) } 3## .data : { *(.data SORT_BY_ALIGNMENT(.data.*) .gnu.linkonce.d.*) } 4## .bss : { *(.bss SORT_BY_ALIGNMENT(.bss.*) .gnu.linkonce.b.*) } 5## This will eliminate most of the padding (~3kb). 6## Hmm, "ld --sort-section alignment" should do it too. 7## 8## There is a ld hack which is meant to decrease disk usage 9## at the cost of more RAM usage (??!!) in standard ld script: 10## . = ALIGN (0x1000) - ((0x1000 - .) & (0x1000 - 1)); . = DATA_SEGMENT_ALIGN (0x1000, 0x1000); 11## Replace it with: 12## . = ALIGN (0x1000); . = DATA_SEGMENT_ALIGN (0x1000, 0x1000); 13## to unconditionally align .data to the next page boundary, 14## instead of "next page, plus current offset in this page" 15*/ 16 17/* To reduce the number of VMAs each bbox process has, 18## move *(.bss SORT_BY_ALIGNMENT(.bss.*) ...) 19## part from .bss : {...} block to .data : { ... } block. 20## (This usually increases .data section by only one page). 21## Result: 22## 23## text data bss dec hex filename 24## 1050792 560 7580 1058932 102874 busybox.bss 25## 1050792 8149 0 1058941 10287d busybox.nobss 26## 27## $ exec busybox.bss pmap $$ 28## 0000000008048000 1028K r-xp /path/to/busybox.bss 29## 0000000008149000 8K rw-p /path/to/busybox.bss 30## 000000000814b000 4K rw-p [ anon ] <---- this VMA is eliminated 31## 00000000085f5000 4K ---p [heap] 32## 00000000085f6000 4K rw-p [heap] 33## 00000000f7778000 8K rw-p [ anon ] 34## 00000000f777a000 12K r--p [vvar] 35## 00000000f777d000 8K r-xp [vdso] 36## 00000000ff7e9000 132K rw-p [stack] 37## 38## $ exec busybox.nobss pmap $$ 39## 0000000008048000 1028K r-xp /path/to/busybox.nobss 40## 0000000008149000 12K rw-p /path/to/busybox.nobss 41## 00000000086f0000 4K ---p [heap] 42## 00000000086f1000 4K rw-p [heap] 43## 00000000f7783000 8K rw-p [ anon ] 44## 00000000f7785000 12K r--p [vvar] 45## 00000000f7788000 8K r-xp [vdso] 46## 00000000ffac0000 132K rw-p [stack] 47*/ 48